The present invention relates generally to the art of heavy machinery and, more particularly, to the art of couplers for loader buckets and the like as used on wheel loaders, tractor loader backhoes and the like. Examples of such couplers are disclosed in commonly assigned U.S. Pat. Nos. 4,708,579, 5,529,419 and 5,692,850, the disclosures of which are hereby expressly incorporated by reference.
It is known to equip couplers for loader buckets and the like with stops that engage the arms or other fixed portion of the associated machinery to prevent further pivoting movement of the coupler and, thus, the bucket or other attachment connected thereto relative to the arms or other fixed structure. For example, couplers for loader buckets typically include a pair of dump stops located on opposite lateral sides of the coupler and adapted to engage the loader arms and prevent pivoting movement of the bucket in a first direction beyond a predefined dump position. Likewise, these couplers include a pair of roll-back stops located on opposite lateral sides of the coupler and adapted to engage to loader arms and prevent pivoting movement of the bucket in an opposite, second direction beyond a predefined roll-back position. These stops are permanently and non-adjustably secured to the coupler body by welding or other means.
These prior, fixed stops are deficient in many respects. First, due to manufacturing tolerances and tolerance build-up, oftentimes the stops do not engage the loader arms as desired. This can lead to stress on the hydraulic cylinder(s) used to pivot the coupler and other components. Secondly, while the stops may perform perfectly on a first loader or other machine carrying the coupler, the stops may not be properly positioned for a different loader or other machine. Thus, a need has been identified for a coupler including adjustable dump and/or roll-back stops.